23 results about "Circumferential strain" patented technology

The invention relates to the technical field of bridge load tests, and provides a bridge load test crack increment change observation method and system, and the method comprises the steps: collecting prestressing tendon circumferential strain distribution data and dual-wavelength strain response data; calculating an interface bonding stiffness change parameter; pre-stress modulation effect compensation and polar coordinate system conversion are carried out on the strain response data and the rigidity change parameters, and micro-crack characteristic signals are obtained; load data and beam group arrangement parameters are collected, and a micro-crack propagation prediction model is established in combination with the interface bonding stiffness change parameters; inputting the micro-crack characteristic signal into a micro-crack propagation prediction model, and outputting a micro-crack development trend prediction result; and adjusting sampling parameters of a dual-wavelength time division multiplexing algorithm and characteristic extraction parameters of prestress modulation effect compensation according to a micro-crack development trend prediction result. According to the invention, the precision of observing the increment change of the micro-crack in the bridge load test is improved, and the automatic monitoring and prediction of the micro-crack of the prestressed concrete bridge are realized.

This invention discloses a method for determining the optimal stable cross-section of a large-span, flat cavern, relating to the fields of geotechnical engineering and underground structure design. The method first establishes a parametric geomechanical model using the cavern span L, crown rise S, and sidewall height H as control parameters. Second, based on the mechanical properties of the surrounding rock, a critical stability criterion is defined, with the comparison of circumferential strain and ultimate strain as its core. Then, using a particle swarm optimization algorithm, under preset geometric constraints and with the critical stability criterion as boundary conditions, a multi-objective iterative optimization calculation is performed on the parameter set (L, S, H). Finally, the target parameter set (Lf, Sf, Hf) that satisfies the critical stability state and has optimal geometric dimensions is output as the optimal stable cross-section solution. This invention automates and optimizes cross-section design, enabling the search for the most economical and efficient cavern cross-section shape while ensuring the self-stability of the surrounding rock, effectively overcoming the shortcomings of traditional design methods that rely on experience and are difficult to optimize.

The invention belongs to the technical field of geotechnical engineering testing, particularly relates to a method for determining composite modulus of waste whole-tire reinforced soil, and aims to solve the problem of data distortion in traditional testing. Comprising the following steps: carrying out a uniaxial tensile test on a waste whole tire to obtain a tire tensile modulus for circumferential stress analysis; the method comprises the following steps: preparing a waste whole tire-filler soil composite sample, carrying out an unconfined compression test, arranging a linear variable differential displacement meter in the diameter direction of the tire to monitor the overall diameter change, and pasting a resistance strain gauge on the inner wall of the tire to measure the local circumferential strain; and calibrating the reading of the resistance strain gauge by using the monitoring result of the linear variable differential displacement meter to obtain calibrated circumferential strain data. And on the basis of a circumferential tension theory, equivalent confining pressure increment provided by the tire to the filler soil is calculated for the obtained calibrated circumferential strain data. And substituting the obtained tire equivalent confining pressure increment into the relationship between the modulus of the filler soil and the confining pressure, and calculating and determining the composite modulus of the waste whole tire reinforced soil.

The application discloses a residual stress detection method in an expansion pipe experimental comprehensive test system. The expansion pipe experimental comprehensive test system is mainly composed of a hydraulic system, an expansion pipe, an expansion cone, a strain collection system, an expansion pipe post-expansion shearing device, an expansion pipe post-expansion anti-external extrusion device and the residual stress detection method. The residual stress detection method is characterized in that the expansion cone is driven to expand the expansion pipe in the axial direction through the hydraulic system, the axial and circumferential strains of the expansion pipe wall during the expansion are collected, the moving distance of the expansion cone is collected in real time through a displacement sensor, the pressure value of the oil pressure of the compression system is collected through a pressure sensor, and then the driving force value during the expansion process is calculated; the post-expansion expansion pipe is subjected to shearing and pressure extrusion resistance experiments, and the residual stress value of the pipe body is detected by using the ring cutting method and the strip cutting method. The residual stress detection method in the expansion pipe experimental comprehensive test system can comprehensively improve the expansion pipe experimental efficiency and the data collection accuracy, and provides reliable data support for the expansion pipe expansion mechanism research.

The application provides a containment concrete temperature strain correction method, device, equipment and medium, and relates to the technical field of nuclear power containment concrete strain correction. The method comprises the following steps: collecting temperature information and strain information of the containment to form a sample set; selecting a preset period of sample sets to form an analysis sample set; based on the assumption that the temperature of the containment cylinder is linearly distributed, the circumferential strain and vertical strain caused by temperature change are obtained; the analysis sample set is fitted by least squares nonlinear fitting to obtain the thermal expansion coefficient temperature correction coefficient of the concrete; and the thermal expansion coefficient and temperature correction coefficient of the concrete obtained are substituted into the formula to obtain the circumferential strain and vertical strain caused by temperature change. The method can accurately evaluate the safety index of the containment, master the actual state of the containment, and optimize the maintenance cost and resources.

The invention relates to the technical field of strain measurement, in particular to a device for measuring micro circumferential strain of a concrete cylinder test piece. In order to solve the problem that the existing method for measuring the micro circumferential strain of the test piece is difficult to test the micro circumferential strain of the test piece, the invention provides a novel device for measuring the micro circumferential strain of the concrete cylinder test piece, which comprises a first arc-shaped frame and a second arc-shaped frame, the first arc-shaped frame and the second arc-shaped frame are each provided with an annular supporting part, the two annular supporting parts are distributed in a bilateral symmetry mode, a first extending part is fixed to the front end of the first arc-shaped frame, a second extending part is fixed to the front end of the second arc-shaped frame, and a clamping spring is arranged between the first extending part and the second extending part. The left side portion of the second extending portion extends leftwards to form a connecting portion, a supporting leg is fixed to the connecting portion, and a displacement sensor is further fixed to the connecting portion. The device is simple in structure, low in manufacturing cost and convenient to use.

This invention belongs to the field of geotechnical engineering testing technology, specifically relating to a method for determining the composite modulus of waste tire reinforced soil, aiming to solve the problem of data distortion in traditional testing. The method includes conducting uniaxial tensile tests on waste tires to obtain the tire tensile modulus for circumferential stress analysis. Waste tire-fill soil composite samples are prepared and subjected to unconfined compression tests. A linear variable differential displacement gauge is placed along the tire diameter direction to monitor the overall diameter change. Resistance strain gauges are attached to the inner wall of the tire to measure local circumferential strain. The readings of the resistance strain gauges are calibrated using the monitoring results of the linear variable differential displacement gauge to obtain calibrated circumferential strain data. Based on circumferential tension theory, the equivalent confining pressure increment provided by the tire to the filler soil is calculated from the obtained calibrated circumferential strain data. The obtained equivalent confining pressure increment is substituted into the relationship between the modulus of the filler soil and the confining pressure to calculate and determine the composite modulus of waste tire reinforced soil.

This optical fiber measurement device (100) for monitoring the axial force of a bolt is provided with: an optical fiber (23) for measuring the strain of an object to be measured; an optical fiber attachment fixing body (25) having an optical fiber attachment nut (21S) to which an optical fiber (23) is attached by changing the shape of the outer peripheral portion of the nut (21) related to at least one combination of the plurality of sets of bolts (20) and nuts (21); and an optical fiber strain distribution measurement unit (24) that measures the circumferential strain distribution of the optical fiber attachment nut (21S) generated by the bolt axial force along the optical fiber (23) attached to the outer peripheral surface of the optical fiber attachment nut (21S), and that measures the circumferential strain and the circumferential strain distribution of the optical fiber attachment nut (21S) in advance by means of the optical fiber strain distribution measurement unit (24). An optical fiber (23) is installed at a specified axial position corresponding to the circumferential strain value or the circumferential strain distribution measured in advance, and the bolt axial force is monitored.

The present invention provides a bellows forming springback control method and mold based on stress regulation, relating to the field of metal processing technology. The method comprises obtaining an expression for the circumferential strain increment based on the principle of material bending deformation; simultaneously establishing an expression for the plastic strain increment, a plastic stress differential equation, and an expression for the circumferential strain increment to obtain an expression for the relationship between the circumferential stress and the axial stress; and, based on the expression for the relationship between the circumferential stress and the axial stress, obtaining a relationship curve with the circumferential compression strain as the independent variable and the ratio of the axial stress to the stress before compression as the dependent variable. After the tube is bent and deformed, the trough can be moved radially toward the axis of the tube along the radial direction of the tube to achieve radial contraction of the trough, thereby increasing the circumferential stress of the trough and reducing the axial stress difference between the inner and outer surfaces, thereby reducing the axial stress of the bellows and effectively controlling the axial springback of the bellows.

The application belongs to the technical field of long-term drift suppression of fiber-optic gyroscope zero bias and scale factor, and particularly relates to a long-term drift suppression method for equivalent sensitive area of a fiber coil. A homogenization, de-homogenization analysis idea and a finite element analysis approach are adopted to establish, verify and calibrate thermodynamic parameters of each non-metallic material of the fiber coil. A mathematical model of long-time drift of circumferential strain, radial strain and three-dimensional stress of a micro-element section of the fiber coil with time, temperature and other environmental conditions is calculated to obtain long-time drift of effective refractive index of each micro-element section. Finally, average long-time drift and dispersion characteristics of the effective refractive index of the fast axis of the fiber coil are obtained, so that long-time drift characteristics of the scale factor of the fiber-optic gyroscope are analyzed. In turn, according to the model, thermodynamic parameters and geometric proportions of each non-metallic material of the fiber coil are optimized to finally realize long-term drift suppression of the equivalent sensitive area of the fiber coil.

The invention belongs to the technical field of underground tension measurement, and particularly relates to a tension sensor measuring circuit and a tensiometer. The device comprises four groups of strain units which are sequentially connected to form a full-bridge circuit, and the strain units on oppositely arranged bridge arms of the full-bridge circuit are respectively a first strain unit and a second strain unit; the two first strain units are arranged in parallel to the axial direction and are used for sensing axial strain; a certain included angle is formed between the two second strain units and the axial direction and is used for sensing circumferential strain; the strain sensitivity coefficient of the second strain unit is different from that of the first strain unit, so that the signal variation of the adjacent first strain unit and second strain unit is the same. The method is used for solving the problems that tension measurement is complex and high in cost, the complex mechanical compensation problem is converted into circuit configuration through source compensation design, and therefore comprehensive optimization is achieved in multiple dimensions such as structural reliability, cost, performance and maintainability, and the method is suitable for petroleum logging scenes with strict requirements.

The application discloses a pipe expanding force testing method, and relates to the field of pipe processing.The method comprises the following steps: selecting a testing pipe section with a length equal to an expanding step along the axial direction of a pipe; selecting at least one cross section of the pipe as a testing cross section along the axial direction of the testing pipe section; selecting at least two strain measuring points on the outer wall of the pipe at the positions of the testing cross sections; obtaining the effective contact area between an expanding die and the inner wall of the testing pipe section during the expanding process; obtaining the circumferential strain of each strain measuring point during the expanding process of the testing pipe section; obtaining the circumferential stress of each strain measuring point through the circumferential strain of each strain measuring point; obtaining the expanding pressure of each strain measuring point through the circumferential stress of each strain measuring point; and obtaining the average expanding force of all the strain measuring points through the effective contact area and the expanding pressure of each strain measuring point, wherein the average expanding force is the pipe expanding force of the expanding die on the testing pipe section.The application can improve the accuracy of pipe expanding force testing.

The invention mainly relates to the technical field of geotechnical engineering tests, and provides a method and a device for calculating deformation parameters of a weathered red-layer soft rock undisturbed sample in order to more accurately determine deformation parameters of red-layer soft rock, the core is that a steel cylinder is adopted to obtain the weathered red-layer soft rock undisturbed sample, the steel cylinder is used as a constraint structure, and the deformation parameters of the weathered red-layer soft rock undisturbed sample are obtained; performing a lateral confinement compression loading test on the sample to obtain the circumferential strain and the axial strain of the outer wall of the steel cylinder in the process; based on the circumferential strain and the axial strain, determining interface axial shear stress between the sample and the inner wall of the steel cylinder, lateral confinement stress of the sample and real axial stress by combining a corrected thick-wall cylinder mechanical model obtained by superposing two groups of loads of the steel cylinder under positive pressure and shearing force; the deformation parameters of the sample are calculated based on the lateral confinement stress and the real axial stress of the sample, the problems of sample preparation failure, structural damage, data distortion and the like caused by the fact that the rock sample must be processed into the standard size in a traditional indoor test are solved, and the deformation parameters of the weathered rock mass can be obtained more accurately.

The invention belongs to the technical field of underground tension measurement, and particularly relates to a tension sensor measuring circuit, a tensiometer and a calculation method. The measuring circuit comprises four groups of strain units, the four groups of strain units are sequentially connected to form a full-bridge circuit, and the strain units on opposite bridge arms of the full-bridge circuit are a first strain unit and a second strain unit respectively; the two first strain units are used for sensing axial strain; each second strain unit comprises at least two strain gauges which are connected in series, at least one strain gauge is obliquely arranged to form a certain included angle with the axial direction and is used for sensing circumferential strain, the other strain gauges are suspended, and the included angle is used for enabling the signal variation of the adjacent first strain unit and second strain unit to be the same. The problem that tension measurement is complex and high in cost is solved, the complex mechanical compensation problem is converted into circuit configuration through source compensation design, and therefore comprehensive optimization is achieved in multiple dimensions such as the structure, reliability, cost, performance and maintainability, and the method is suitable for petroleum logging scenes with strict requirements.

This invention discloses a method for monitoring the overall deformation of tunnels based on distributed optical fiber sensing and complex variable function method, belonging to the field of underground engineering structural health monitoring technology. The method includes: S1, constructing a displacement inversion analytical model: based on the complex variable function theory of elasticity and conformal mapping method, a displacement inversion analytical model for strain-to-displacement conversion is established; S2, distributed strain data acquisition: distributed strain sensing optical fibers are circumferentially deployed on the inner surface of the non-circular tunnel lining, and optical frequency domain reflection technology is used to collect circumferential strain distribution data of the entire cross-section of the non-circular tunnel in real time; S3, strain-displacement conversion calculation: the collected circumferential strain data is input into the displacement inversion analytical model, and the continuous displacement distribution of the inner wall of the non-circular tunnel is inverted through numerical calculation. This method not only accurately captures the details of strain abrupt changes in key parts such as the tunnel arch and corners, but also accurately converts strain data into intuitive displacement information.

The present application relates to the technical fields of strain measurement, in particular to a device for measuring the micro hoop strain of a concrete cylinder specimen. In order to solve the problem that the existing method for measuring the micro hoop strain of a specimen is difficult to test the micro hoop strain of the specimen, a new device for measuring the micro hoop strain of a concrete cylinder specimen is provided, which comprises a first arc-shaped frame and a second arc-shaped frame, and the first arc-shaped frame and the second arc-shaped frame are both provided with a hoop support part, the two hoop support parts are symmetrically distributed left and right, the front end of the first arc-shaped frame is fixed with a first extension part, the front end of the second arc-shaped frame is fixed with a second extension part, a clamping spring is arranged between the first extension part and the second extension part, the left side of the second extension part extends leftward with a connecting part, the connecting part is fixed with a supporting leg, and the connecting part is also fixed with a displacement sensor. The device has simple structure, low manufacturing cost and is convenient to use.

The invention discloses a method for determining an optimal stable section of a large-span flat cavern, and relates to the technical field of geotechnical engineering and underground structure design. The method comprises the following steps: firstly, establishing a parameterized geomechanical model by taking a cavern span L, a vault rise S and a side wall height H as control parameters; secondly, based on the mechanical characteristics of the surrounding rock, defining a stability critical criterion taking the comparison of circumferential strain and limit strain as a core; then, through a particle swarm optimization algorithm, under a preset geometric constraint, taking a stability critical criterion as a boundary condition, carrying out multi-target iterative optimization calculation on the parameter set (L, S, H); and finally, outputting a target parameter group (Lf, Sf, Hf) which meets the critical stable state and has the optimal geometric dimension, and taking the target parameter group (Lf, Sf, Hf) as an optimal stable section solution. According to the method, automation and optimization of section design are achieved, the most economical and efficient cavern section shape can be sought on the premise that self-stabilization of surrounding rock is guaranteed, and the defects that a traditional design method depends on experience and is difficult to optimize are effectively overcome.

The present application discloses a kind of present-day ground stress inversion method based on well wall strain monitoring, including in the local well wall wall surface of the far away from the influence area of orifice and hole bottom in ground stress measurement borehole three groups of right angle strain flowers are placed in the same horizontal position;On the well wall mud column pressure is applied, while recording the strain value on the strain flower, then respectively determine the circumferential strain and axial strain at 3 positions on the well wall;According to the relationship between the elastic theory and the global stress field of the measured point hole wall strain at different positions, the maximum and minimum horizontal stresses of the in-situ stress field at the three positions on the well wall are determined;According to the maximum and minimum horizontal stresses of the in-situ stress field at the three positions, the average value is obtained to determine the maximum and minimum horizontal stresses of the actual in-situ stress field.The present application can make up for the deficiency of traditional stress test, compared with traditional stress test, it is not necessary to drill core on the well wall, avoiding the complex construction process, saving the manpower and material resources required for drilling core.

The invention discloses an oil and gas pipeline dynamic leakage prediction method and system, and relates to the technical field of oil and gas pipeline monitoring, and the method comprises the steps: synchronously collecting the pressure, flow and orthogonal circumferential strain sequence of a monitoring pipe section; calculating an equivalent elliptical sectional area based on the strain, and constructing an elliptical breathing nonlinear anomaly index in combination with a pressure sequence; performing nonlinear correction on the geometric volume variation of the pipe section by using the index to obtain a corrected respiratory storage volume; generating a leakage precursor index based on the inlet and outlet flow difference and the correction quantity; and finally, judging the leakage trend grade according to the steady threshold value of the leakage-free historical data. According to the invention, the accuracy and false alarm resistance of leakage early warning can be obviously improved.

The application discloses a kind of method and system for monitoring pipeline wall thickness in real time based on strain measurement, the initial circumferential strain and initial axial strain of the position of the pipeline to be measured are measured, the circumferential strain and axial strain caused by the internal pressure of pipeline are obtained, the relationship between the strain is obtained, and drift correction is carried out, the circumferential drift and axial drift in a cycle are solved, the circumferential strain and axial strain caused by the internal pressure of pipeline after correction are obtained, the dynamic pressure in pipeline is calculated, and the initial pulsating pressure maximum of pipeline is obtained;Real-time circumferential strain and real-time axial strain are obtained by real-time measurement, and drift correction is carried out, and the maximum value of the circumferential strain and axial strain caused by the internal pressure in each cycle after correction is obtained;According to the initial pulsating pressure maximum, the maximum value of the circumferential strain and axial strain caused by the internal pressure in each cycle after correction, the pipeline inner diameter is solved, the real-time wall thickness of the pipeline to be measured is obtained, and the wall thickness of the pipeline can be monitored in real time.

The application relates to a cable force size measuring device and method based on an anchor cup strain, which comprises the following: an anchor base body, one end of which is a U-shaped ear end, and the other end is a round table-shaped anchor cup end; eight resistance strain gauges, four of which are longitudinally arranged on the anchor cup end and used for measuring the axial strain of the anchor cup end, and four of which are transversely arranged on the anchor cup end and used for measuring the circumferential strain of the anchor cup end, the four longitudinally arranged resistance strain gauges are connected in series to form a first branch and a fourth branch, the four transversely arranged resistance strain gauges are connected in series to form a second branch and a third branch, and the four branches are connected in parallel to form a Wheatstone full-bridge circuit; and a signal acquisition and transmission device connected to the Wheatstone full-bridge circuit through wires. The application can realize real-time and accurate measurement of the cable force size during the service of the cable, and can be used for the construction and service stage of the cable net structure in a building structure and the bridge cable.

The invention relates to the field of surrounding rock reinforcement, in particular to a high-internal-pressure gas storage surrounding rock grading method and system.The method comprises the steps that first information, design internal pressure and geometric dimension parameters of a gas storage and material mechanical property parameters of a lining and a sealing structure are obtained; performing inversion processing according to the first information to obtain a three-dimensional mechanical field model; performing circumferential strain field prediction processing according to the three-dimensional mechanical field model and the designed internal pressure and geometric dimension parameters to obtain a circumferential strain field cloud picture and a key part strain-time evolution curve of the lining; performing multi-dimensional dynamic risk grading processing according to the circumferential strain field cloud picture, the key part strain-time evolution curve and the material mechanical property parameters to obtain a surrounding rock risk grade evaluation result; and a reinforcement scheme is determined according to a surrounding rock risk grade evaluation result. The method effectively avoids the problem of safety risk or excessive conservative caused by an indefinite mechanical mechanism in a traditional method.

The invention discloses an in-service wind power blade load dynamic monitoring and overload early warning method, which comprises the steps of analyzing blade section stress under different wind conditions, and identifying a maximum dangerous section by taking a maximum equivalent stress criterion as a failure judgment basis as an optimal monitoring position of a strain sensor; determining an optimal strain sensor installation number according to a finite element circumferential strain deformation result at the maximum dangerous section and a sensitive grid effective monitoring range of the strain sensor; establishing a resistance or voltage and load measurement model to realize dynamic load monitoring of the in-service blade; and the blade overload judgment and early warning are realized by comparing the delivery design load of the blade with the load data obtained by monitoring. According to the method, dynamic load monitoring and overload early warning of the in-service wind power blade can be accurately achieved by installing the stress sensor at the maximum dangerous section, wind power output is further optimized and controlled by synchronously increasing monitoring of wind parameters with large influences such as wind shear and turbulence, and the anti-fatigue performance of the in-service wind turbine generator blade is improved.